methyl 3,5-dihydroxybenzoate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:47.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a flask fitted with thermometer, condenser, overhead stirrer, pH probe and nitrogen line was added methyl-3,5-dihydroxybenzoate (1.0 eq), 325 mesh potassium carbonate (3.0 eq) and dimethylformamide (DMF) (4 vols) under a nitrogen atmosphere. The mixture was heated to 47° C. for 1 hour, then benzoyl chloride (1.0 eq) was added slowly drop-wise via syringe pump over approximately 2 hours. Further benzoyl chloride was added (0.1 eq) over 20 minutes via syringe pump. The reaction mixture was held for 1.5 hours, then water (10 vols) and iso-propyl acetate (6 vols) were added. The reaction mixture was agitated for 30 minutes and then the layers were separated. The aqueous layer was re-extracted with a further charge of iso-propyl acetate (6 vols). The batch was separated, and the combined organic layers were washed with saturated brine (6 vols), then with a solution of 0.1N hydrochloric acid/brine. The iso-propyl acetate was distilled to dryness on the rotary evaporator. Iso-propyl acetate (6 vols) was added, and distilled to dryness on the rotary evaporator. Toluene (6 vols) was added and distilled to dryness on the rotary evaporator. Toluene (3.5 vols) was added and the reaction slurried for 30 minutes. The solid was filtered off and dried at 20° C.-40° C. to give the desired product as a solid (corrected yield 72%). To a flask fitted with thermometer, condenser, overhead stirrer, pH probe and nitrogen line the layers were separated The aqueous layer was re-extracted with a further charge of iso-propyl acetate (6 vols) The batch was separated the combined organic layers were washed with saturated brine (6 vols) The iso-propyl acetate was distilled to dryness on the rotary evaporator Iso-propyl acetate (6 vols) was added distilled to dryness on the rotary evaporator Toluene (6 vols) was added distilled to dryness on the rotary evaporator Toluene (3.5 vols) was added the reaction slurried for 30 minutes The solid was filtered off dried at 20° C.-40° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a flask fitted with thermometer, condenser, overhead stirrer, pH probe and nitrogen line was added methyl-3,5-dihydroxybenzoate (1.0 eq), sodium phosphate mono-basic monohydrate (0.46 eq) and water (10.5 vols) under a nitrogen atmosphere. The temperature was adjusted to 20° C.±3° C. 10% w/w Sodium hydroxide was added to adjust the pH to pH 7.8±0.2. Benzoyl chloride (1.0 eq) was added drop-wise in small portions over 1-2 hours, and sodium hydroxide was added concurrently drop-wise in small portions over the same time period to maintain the reaction in a pH range of pH 7.8±0.2 and at a reaction temperature of 20° C.±3° C. The crude reaction mixture was agitated for a further 30 minutes, filtered, and then washed with 4 vols of a solution prepared from water (4 vols), sodium phosphate mono-basic monohydrate (0.05 eq), and adjusted to pH7.5 with 10% w/w sodium hydroxide. The crude solid was then washed with 4 vols of a solution prepared from water (4 vols), sodium phosphate mono-basic monohydrate (0.05 eq), and adjusted to pH6.5 with 10% w/w sodium hydroxide. The crude solid was then dissolved in iso-propyl acetate (8 vols) and water (2 vols) and the mixture agitated for at least 30 minutes to ensure the solid had dissolved. The mixture was filtered through a CUNO™ filter to remove a small amount of brown solid. The aqueous layer was separated off. Water (2 vols) was added to the organic layer and the batch agitated for at least 30 minutes. The aqueous layer was separated off and the organic layer was vacuum distilled, keeping the batch temperature below 40° C. to reduce the volume to 5-6 vols. Toluene was added then added (5 vols) and the mixture was vacuum distilled keeping the batch temperature below 40° C., reducing the volume to approximately 3.5 vols. The mixture was cooled to 15° C.±3° C. and agitated at this temperature for at least 30 minutes, then filtered, and the solid washed with toluene (1 vol). The product was dried at 20° C.-40° C. to give the desired product as a solid (corrected yield 40%-70%). To a flask fitted with thermometer, condenser, overhead stirrer, pH probe and nitrogen line was adjusted to 20° C.±3° C to maintain the reaction in a pH range of pH 7.8±0.2 at a reaction temperature of 20° C.±3° C The crude reaction mixture filtered washed with 4 vols of a solution The crude solid was then washed with 4 vols of a solution had dissolved The mixture was filtered through a CUNO™ filter to remove a small amount of brown solid The aqueous layer was separated off Water (2 vols) was added to the organic layer the batch agitated for at least 30 minutes The aqueous layer was separated off distilled the batch temperature below 40° C. Toluene was added then added (5 vols) distilled the batch temperature below 40° C. The mixture was cooled to 15° C.±3° C. agitated at this temperature for at least 30 minutes filtered the solid washed with toluene (1 vol) The product was dried at 20° C.-40° C.